The present invention generally relates to nano-composites and compositions including the nano-composite (also referred to as an organo-clay). More particularly, the present invention relates to a nano-composite comprising a cationic mediator and a clay, a polymer electrolyte composition comprising a cationic mediator and a solvent, a moisture reducing composition comprising a cationic mediator, the manufacture thereof, and industrial applications therefore.
Since the discovery of exfoliated nylon/clay nanocomposites by Usuki et al. (J. Mater. Res. 1993, 8, 1174), there have been extensive efforts to prepare various polymer-layered material composites. The most common morphology for miscible polymer-layered material dispersions is known as intercalation and exfoliation, which provides a polymer having improved mechanical, permeability, thermal, and heat distortion temperature properties. However, for polymers, particularly nonpolar polymers, well-exfoliated polymer-layered material nanocomposites are notoriously difficult to obtain.
Gas impermeability is an important characteristics for many polymer products, for example, butyl rubber. However, unsaturated bonds in butyl rubber, contributed by the presence of isoprene monomer units in the backbone, can be attacked by atmospheric ozone. These attacks may, over time, lead to oxidative degradation, which may subsequently lead to chain cleavage. As such, there exists a continuous interest in lowering gas permeability of polymers.
One technique for lowering gas permeability is using well-exfoliated layered materials as an additive. However, the effort to improve gas permeability must be balanced against damaging other polymer properties such as vulcanization plateau, Shore A hardness, cure capability, rubber damping properties, cure time, modulus, stress-strain, and moisture absorption, in order to achieve an overall superior performance. For example, although they reduce gas permeability, organo-clays derived from some organic ammonium salts of low decomposition temperature, may damage or retard the cure process of the rubber compound, especially, when using free radical cure, sulfur cure, ZnO cure and etc.
The present invention provides nano-composites based on a cationic mediator which is comprised of a polymeric group and a cationic unit selected from the group consisting of onium cation and heterocyclic cation. According to selected embodiments, the invention employs green solvents, e.g. 1-methylimidazol, as the reactants in preparing the cationic mediator, making both the process and product relatively environmentally friendly.